1. Field of the Invention
The present invention relates to a display device utilizing a head mount display or another stereoscopic display device which generates stereoscopic images by computer graphics utilizing parallax of both eyes of a human being, and a recording media where a program for executing the image processing is recorded.
2. Description of the Related Art
A purpose of computer graphics is providing actual sensations to a user, as if being in the scene, and for ordinary display screens, which are two-dimensional planes, various means are used to represent in the two-dimensional plane an object in a three-dimensional space which actually exists. A head mount display, in particular, intends to give sensations to the user, just like looking at the external world with his/her own eyes by such a display as a liquid crystal display, mounted directly before both eyes of the user.
FIG. 6 shows a schematic diagram depicting the status where a user is looking at images created by computer graphics, on a head mount display. Computer graphics are created based on the view point of the user, indicated by the left eye 30 and the right eye 32 of the user. In the example of FIG. 6, objects A34, B35 and C36 exist in a virtual three-dimensional space of computer graphics. The computer graphic images are created for the left and right eyes, by converting an object in three-dimensional space to perspective views on the two-dimensional planes of the left and right display screens respectively, where view points are positions of the left eye 30 and the right eye 32 respectively, and the lines of sight direction from the right and left view points are the direction toward a point at infinity. Then the user will see three-dimensional stereoscopic images on the head mount display utilizing parallax caused by different view point positions of the left and right eyes 30 and 32.
When three-dimensional stereoscopic images are created by computer graphics and are viewed by a head mount display utilizing parallax of both eyes, as described above, images when an object is approaching the user are sometimes seen as unnatural. This is because when human eyes see an object at close range, the lines of sight move inward according to the distance of the object, but with computer graphics, perspective conversion is performed by fixing the line of sight to a point at infinity, regardless the distance from the human eyes to the attention target object.
Therefore an object of the present invention is to provide a head mount display or another stereoscopic display device that generates natural images, similar to images as a human being actually sees as a moving object, when stereoscopic images created by computer graphics utilizing parallax of both eyes are seen, and a method for generating computer graphic images.
The above objective can be achieved by a display device in accordance with the present invention which utilizes a display screen which displays images for right and left eyes, and comprises: a drawing circuit which generates image data for the right and left eyes by perspective conversion processing according to object data to be displayed and to view point data including view point position and light of sight directions; and image processing unit which determines an attention target object from the plurality of objects to be displayed according to the distance from the view point position to the object position, modifies the line of sight directions for the images for the right and left eyes according to the distance from said view point to the attention target object, and provides view point data including the modified line of sight directions and object data to the drawing circuit.
If the attention target object comes closer, the line of sight directions corresponding to the left and right screens are modified according to the distance between the object and view point position, and perspective conversion is performed based on the modified line of sight directions, therefore images displayed on the head mount display or another stereoscopic display can conform to natural human perception.
The above object can also be achieved by providing a computer-readable recording medium recording a program for generating a view point data and an object data, for a stereoscopic display device including: a display screen which displays images for right and left eyes, and a drawing circuit that generates image data for said right and left eyes by perspective conversion processing according to the view point data including a view point position and line of sight directions, and the object data to be displayed, said program executing image processing procedure of:
determining an attention target object from said plurality of objects to be displayed according to the distance from said view point position to said object position,
modifying the line of sight directions for said images for the right and left eyes according to said distance, and
inputting said view point data and the object data to the drawing circuit.
As a consequence, an object the human being will pay attention to can be forecasted according at least to the distance between the object and the view point direction, and a realistic stereoscopic image can be displayed by changing the line of sight directions dynamically to the direction of the object.
The above stereoscopic display can be applied to not only a head mount display device and also another stereoscopic display device, in which an image for right eye and an image for left eye are displayed frame by frame alternately, and right and left shutters provided between the display and right and left eyes are closed or opened alternately in sync with the images. Further, there has been proposed a stereoscopic display device which includes a lenticular lens or parallax barrier between the display and human beings so that human beings does not necessary to wear any eye glasses or head mount display. This type stereoscopic display device can also employ the present invention.